If we had two independent samples, the variance is known and $n_1$ and $n_2$ are bigger than 30, the test statistic for the difference between the two population means is calculated as:

$z=\frac{x_1-x_2}{\sqrt{\frac{s_1^2}{n_1}+\frac{s_2^2}{n_2} } }$

Where $x_1$ and $x_2$ are the means of the samples, $s_1^2$ and $s_2^2$ are the variances of the samples and $n_1$ and $n_2$ are the size of the sample.

Finally, replacing $x_1$ by 82, $x_2$ by 88, $s_1^2$ by 112.5 , $s_2^2$ by 54, $n_1$ by 45 and $n_2$ by 36, we get that the statistic is equal to:

$z=\frac{82-88}{\sqrt{\frac{112.5}{45}+\frac{54}{36} } }=-3$

6 0

3 years ago

A triangle inscribed in a semicircle can be identified as a/an _______ triangle.

Lena [83]

A triangle inscribed in a semicircle can be identified as a/an isosceles triangle. It is a triangle that has two sides of equal length. It has 2 equal sides and 2 equal angles. Hope this answers the question. Have a nice day.

4 0

3 years ago